Overlap and temporal variation in the diets of sympatric Antarctic and Subantarctic fur seals (Arctocephalus spp.) at Marion Island, Prince Edward Islands

dc.contributor.authorReisinger, Ryan Rudolf
dc.contributor.authorLandman, Marietjie
dc.contributor.authorMgibantaka, Nonkoliso
dc.contributor.authorSmale, Malcolm J.
dc.contributor.authorBester, Marthan Nieuwoudt
dc.contributor.authorDe Bruyn, P.J. Nico
dc.contributor.authorPistorius, Pierre Anton
dc.date.accessioned2018-06-12T07:33:19Z
dc.date.available2018-06-12T07:33:19Z
dc.date.issued2018-04-20
dc.description.abstractAntarctic (Arctocephalus gazella) and Subantarctic (A. tropicalis) fur seals are important predators in the Southern Ocean. Marion Island (southern Indian Ocean) hosts the largest sympatric breeding populations of these two species. Environmental and population changes here over two decades may have influenced their diet and trophic interactions. To quantify diet, we analysed prey remains in scat samples from Antarctic (661 scats) and Subantarctic (750 scats) fur seals collected at Marion Island (2006–2010). We assessed diet composition over time and calculated dietary overlap. The diet of both species was dominated by fish prey (98.2% and 99.4% of prey items), mainly myctophids. Antarctic fur seals consumed small numbers of penguins, cephalopods and crustaceans. In Subantarctic fur seal scats, crustaceans and cephalopods were rare and penguin remains were absent. The diets of the two species overlapped substantially (Pianka’s index = 0.98), however, small but significant differences in the relative proportions of prey were evident. Seasonal and annual diet changes suggest that their diet is similarly influenced by patterns of local prey availability and abundance. Despite substantial changes in the population size and trajectory of Antarctic and Subantarctic fur seals – which would be expected to influence trophic interactions between them – comparing our data to those from earlier studies (1989–2000) did not reveal significant long-term dietary changes in either species.en_ZA
dc.description.departmentMammal Research Instituteen_ZA
dc.description.departmentZoology and Entomologyen_ZA
dc.description.librarianam2018en_ZA
dc.description.sponsorshipThe National Research Foundation (South Africa) under grant number SNA93071. RRR was supported by a National Research Foundation SANCOR post-doctoral fellowship (grant 94916).en_ZA
dc.description.urihttp://www.tandfonline.com/loi/zpor20en_ZA
dc.identifier.citationRyan R. Reisinger, Marietjie Landman, Nonkoliso Mgibantaka, Malcolm J. Smale, Marthán N. Bester, P.J. Nico De Bruyn & Pierre A. Pistorius (2018) Overlap and temporal variation in the diets of sympatric Antarctic and Subantarctic fur seals (Arctocephalus spp.) at Marion Island, Prince Edward Islands, Polar Research, 37:1, 1451142, DOI: 10.1080/17518369.2018.1451142.en_ZA
dc.identifier.issn0800-0395 (print)
dc.identifier.issn1751-8369 (online)
dc.identifier.other10.1080/17518369.2018.1451142
dc.identifier.urihttp://hdl.handle.net/2263/65133
dc.language.isoenen_ZA
dc.publisherCo-Action Publishingen_ZA
dc.rights© 2018 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial License (http://creativecommons.org/licenses/by-nc/4.0/).en_ZA
dc.subjectPreyen_ZA
dc.subjectScatsen_ZA
dc.subjectForagingen_ZA
dc.subjectMarine mammalen_ZA
dc.subjectPinnipeden_ZA
dc.subjectConfidence interval (CI)en_ZA
dc.subjectPermutational multivariate analysis of variance (PERMANOVA)en_ZA
dc.subjectWinteren_ZA
dc.subjectAntarctic fur seal (Arctocephalus gazella)en_ZA
dc.subjectSubantarctic fur seal (A. tropicalis)en_ZA
dc.subjectPup growthen_ZA
dc.subjectMarion Island, Prince Edward Islandsen_ZA
dc.subjectStable isotopeen_ZA
dc.subjectSeasonal changesen_ZA
dc.subjectForaging behavioren_ZA
dc.subjectPopulation changesen_ZA
dc.subjectSouthern Ocean predatoren_ZA
dc.titleOverlap and temporal variation in the diets of sympatric Antarctic and Subantarctic fur seals (Arctocephalus spp.) at Marion Island, Prince Edward Islandsen_ZA
dc.typeArticleen_ZA

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